Apparatus for charging blast furnaces



y 1950 R. s. A. DOUGHERTY ETAL ,1 0

APPARATUS FOR CHARGING BLAST FURNACES Filed April 7, 1945 fiabert fioalggrg Patented July 25, 1950 APPARATUS FOR CHARGING BLAST FURNACES Robert S. A. Doughert Bethlehem, I'm, minors to Company,

y and John E. Eberhardt,

Bethlehem Steel a corporation of Pennsylvania Application April 7, 1945, Serial No. 587,106

9 China.

This invention relates in general to an apparatus and method for the operation of blast furnaces. and more particularly to an apparatus and method for preventing the erosive wear of blast furnace parts incident to the leakage of dustladen gases.

It has been discovered that by working blast furnaces at higher top pressures than normal there accrue benefits in smoothness of operation, decreased dust losses, increased tonnage, and decreased coke/ore ratio.

Bell-and-hopper structures, however, cannot be made perfectly gastight, even for ordinary pressures, and at high pressures the strong erosive action of the dust-laden gases escaping through the numerous unavoidable leaks very quickly causes excessive wear. It should be noted, however, that the rate of wear is increased only at the places where the leakage occurs. Within the furnace, oiftakes, etc., the erosive ell'ect of the dirty gases is less, because of their lower velocity.

One object of this invention, therefore, is to provide means for permitting eillclent and economical use of high top pressures in blast turnaces.

Another object is to provide means for preventing excessive wear of blast furnace bells and hoppers due to leakage of erosive dust-containing gases.

Other objects and purposes of the invention will appear hereinafter in the specification and in the appended claims.

Referring now to the attached sheet of drawing, the single diagrammatic figure thereon illustrates a blast furnace top I, provided with the offtake 2, and three superposed charge-receiving hopper chambers comprising the upper hopper chamber 3, the intermediate hopper chamber 4. and the lower hopper chamber 5, through which hopper chambers the materials may drop successively to the furnace stack I. Each hopper chamber is provided as shown with a bell, comprising the small bell 1 closing the bottom of hopper chamber 3, the intermediate bell closing the bottom of hopper chamber 4, and the large hell 9 closing the bottom of hopper chamber 5. Manipulating means for lowering and raising the bells comprise the rod I II, attached to the bell 9, and the concentric sleeves ii and I! attached to the bells 8 and 1 respectively.

The lower hopper chamber is provided with the pipe H for admitting clean outside gases to said hopper chamber. The pipe l4 provided with equalizing valve [5 connects the hopper chambers 4 and 5, and the relief valve i6 and pipe H vent the intermediate hopper chamber 4 to the atmosphere.

In practice, the gas pressure in the furnace stack 6 is controlled at the point of most eillcient operation for the particular blast furnace, but the pressure in the lower hopper chamber I in in the furnace stack charge into said hopper chamber 4. Said small bell 1 being raised again into position, the relief valve I6 is closed and the equalizing valve I 5 is opened. Gas then flows through pipe l4 until the pressure in hopper chamber 4 equals that in hopper chamber 5, permitting the intermediate bell 8 to be lowered and thereby dropping the materials of the charge into said hopper chamber 8. Equalizing valve I 5 is then closed and relief valve It opened and the above described cycle is repeated until the proper number of charges has been placed in hopper chamber 5. Since the pressure in hopper chamber 5 is maintained at all times slightly in excess of that in the furnace stack 6, the large bell 9 may be lowered at the proper time thereby dropping the materials being charged into said furnace stack 6.

The small leakage of clean gas from the hopper chambers 4 and Erwin have no erosive effect on the bell seats or other parts, and likewise there will be no trouble from clogging or wear due to dust in the pipe l4 or equalizing valve l5. It is necessary to clean the blast furnace gas in any event, for use in blowing engines, stoves, boilers, etc., so the return of a small portion in this manner will impose only the slight additional expense of compressing it to the desired pressure.

Although we have hereinabove described our invention in considerable detail, we do not wish to be limited narrowly to the exact and specific particulars disclosed, but may use such substitutes, modifications, or equivalents as are included within the scope and spirit Of the invention or pointed out in the appended claims.

In accordance with the statute, we desire to claim:

1. In the charging mechanism for operating a blast furnace comprising three superposed hopper chambers above the stack, means for introducing clean gas at a higher than stack pressure into the bottom hopper chamber; and means for transferring said gas from said bottom chamber into the next above hopper chamber when required to equalize pressures therebetween.

2. In the charging mechanism on the top of a blast furnace above the stack, the combination of a plurality of hopper chambers, each having a bottom bell, superposed above said stack, and means for maintaining a higher than stack pres- 3 sure of clean gases in one or more ofsaidhoppep chambers. a

3. In the charging mechanism on the top of ablast furnace above the stack chamber, the combination of a hopper chamber having a bottom bell opening into the stack chamber, a pipe line for admitting clean gas at a pressure in excess of that of the gases in the stack chamber into said hopper chamber, a second hopper chamber having a bell opening into the ilrst hopper chamber,

said receiving-hopper and discharging it into said delivery-hopper, means to intermittently open and"close said intermediate-hopper bell.

means to deliver substantially-nonabradant inert a second pipe line having a valve for equalizing gas at higher pressure than that in the top portionp'i the furnace into said lower chamber and maintain said higher gas-pressure therein during the operation of the furnace, means to feed substantially-nonabradant inert gas under said higher pressure into said first chamber, means to control thefeed of said gas into said first chamber to equalize the pressures on the opposite sides-of said intermediate-hopper bell prior to hoppers together, and means to feed chargingQ-zo material into said receiving-hopper intermit, te'ntly, the novel improvementof the combina-, tion of means including a valve-construction in said conduit dividing said conduit into an upper chamber and a lower chamber, the latter including said delivery-hopper, means to open and close said valve-construction intermittently, means to i'eed substantially-nonabradant inert gas under pressure into said lower chamber and maintain the gas-pressure in said lower chamber at all times greater than the gas-pressure in the top portion of the furnace, means to feed substani ti'ally-nonabradant inert gas under said specified pressure into said upper chamber, means controlling said gas fed into said upper chamber to maintain equalized gas-pressures on opposite sides of said valve prior to and during the open condition of the latter, means connecting said upper chamberto the external-atmosphere, and means controlling the passage of gas from saidfirst chamber to the atmosphere to provide atmospheric-pressurein said upper chamber on the underside of said receiving-hopper bell prior, to and during the open condition of said bell.

.5. The novel combination in a blast-furnace charging-system set forth in claim 4, in which said valve-construction includes an intermediatehopper and its bell discontinuously receiving the charging material discharged from said receivlug-hopper and interruptedly dumping it into said delivery-hopper.

:6.- In the charging-system of a blast-furnace operating under a high gas-pressure in its top portion, said charging-system having an upper receiving-hopper internally at approximately atmospheric-pressure and its bell, actuatingmeans intermittently opening and closing said bell, a lower delivery-hopper and its bell dis-- charging into .the top portion of the furnace, a conduit connecting said hoppers together, and means to feed charging material intermittently into said receiving hopper, the novel improvement of the combination of an intermediate hopper and its bell in said conduit between said, hopper and dividing said conduit into an upper chamber and a lower chamber, the latter including said'delivery hopper, said intermediatehopper and its bell acquiring its material from,

'furnace during operation of the latter.-

.9. In: a blast-furnace charging-system ofits opening and while it remains open, means connecting said upper chamber tothe externalatmosphere,-. and: means controlling the passage ofigas therethroughtcwthe atmosphere to provide substantially atmospheric gas-pressure insaid:

receiving-hopper bell and while the: latter is known type havlngran upper.,-receiving-hopper and. its' bell,- actuating-meansopeningand closchamber priomto the opening of. said' blast-furnace -lcharging-system 0! ing said bell intermittently; a; lower delivery-- happen and its. .bell discharging into the top "of the ,furnace-. andoperating-means opening and closing ,saiddelivery-hopper bellintermittently, the -novel improvement of-rmeans for continucusly; maintainingthe interior of-said 'deliveryhopperwith substantially-nonabradant inert gas at a super-atmospheric; pressure greater than that inthe. top of therfurnace during the operation-of the latter.-

8.--In' a .blast-rurnace. charging-system ofknown type having "an upper'receiving-hopper and-its; bell, actuating-means opening and 'clos- Y ing said bell' intermittently, a lower delivery hopper and its bell discharging into the top of the furnace; and operating-means, opening and closing said delivery-hopper bell intermittently,

the'novel-improvement of means for continuously maintaining the interior of said delivery-hopper with-substantially-nonabradant inert gas at a super-atmospheric pressure than the gas-pressure in the top portion at all times greater of the known type having an upper receiving-hopper and its bell, actuating-means openingand clos lng said bell intermittently, a lower delivery-' hopper and its-bell discharging into the top of the furnace, andoperating-means opening and closing-said delivery-hopper bell intermittently,

the novel improvement of means to maintain at fall times a pressure in said delivery-hopp r with Substantiallywcnabradantinert gas at a pressure greater than the super atmospheric pressure in the top portion of the furnace during the Number Name Date 2,200,488 Ciemittet al. May 14, 1940 2,215,872 Fox et a1 Sept. 24, 1940 2,408,945 Mohr et al.= Oct. 8, 1946 

